Study

Species-rich plantings increase biomass and nitrogen accumulation in a wetland restoration experiment

  • Published source details Callaway J.C., Sullivan G. & Zedler J.B. (2003) Species-rich plantings increase biomass and nitrogen accumulation in a wetland restoration experiment. Ecological Applications, 13, 1626-1639

Actions

This study is summarised as evidence for the following.

Action Category

Restore/create brackish/saline marshes or swamps (multiple actions)

Action Link
Marsh and Swamp Conservation

Directly plant non-woody plants: brackish/saline wetlands

Action Link
Marsh and Swamp Conservation
  1. Restore/create brackish/saline marshes or swamps (multiple actions)

    A study in 1996–2000 of a salt marsh restoration site in California, USA (Callaway et al. 2003) reported that three growing seasons after multiple interventions, the site contained both planted and unplanted vegetation. On average, plots contained 94 g/m2 standing above-ground biomass if not planted, and 372–431 g/m2 standing above-ground biomass if planted (see Action: Directly plant whole plants). Unplanted species colonized all plots, but only five species were found across 15 unplanted plots. Three species comprised 97% of the above-ground biomass in unplanted plots: dwarf saltwort Salicornia bigelovii (59 g/m2), pickleweed Salicornia virginica (29 g/m2) and estuary seablite Suaeda esteroa (5 g/m2). Methods: In 1996/1997, an upland area was lowered to intertidal elevations and graded into a slope. In this area, eighty-five 4-m2 study plots were amended with fine sediment, tilled and levelled. Seventy plots were then planted with salt marsh herbs/succulents (90 seedlings/plot; 1–6 species/plot; eight species total). Non-planted vegetation was cleared from all plots in 1997 and 1998, but was left to grow from 1999. In January 2000, standing vegetation was cut from a 20 x 120 cm quadrat in each plot, then dried and weighed. This study was based on the same experimental set-up as (2) and (6).

    (Summarised by: Nigel Taylor)

  2. Directly plant non-woody plants: brackish/saline wetlands

    A replicated, randomized, paired, controlled study in 1997–2000 in an estuary in California, USA (Callaway et al. 2003) found that plots planted with salt marsh vegetation contained more above-ground plant biomass, after three growing seasons, than unplanted plots. Results summarized for this study exclude litter and are not based on assessments of statistical significance. On average, plots planted with 3–6 species contained 372–431 g/m2 biomass whilst plots planted with a single species contained 277 g/m2 biomass. Unplanted plots contained only 94 g/m2 biomass. In single-species plots, the biomass of the planted species ranged from <1 g/m2 (arrowgrass Triglochin concinna) to 490 g/m2 (pickleweed Salicornia virginica). The biomass of unplanted species in these plots was 1–102 g/m2. Methods: In spring 1997, eight salt marsh herbs/succulents were planted into recently reprofiled intertidal sediment. In each of five areas, 14 random 4-m2 plots were planted with 90 greenhouse-reared seedlings (eight single-species plots, three three-species plots, three six-species plots) and three random plots were left unplanted. The planting areas had recently been excavated, amended with fine sediment, tilled and levelled. Non-planted vegetation was cleared from all plots during the first two growing seasons (1997–1998), but was left to grow in the third (1999). In January 2000, standing vegetation was cut from a 20 x 120 cm quadrat in each plot, then dried and weighed. This study was based on the same experimental set-up as (12), (13) and (16).

    (Summarised by: Nigel Taylor)

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 18

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust